<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>媒体查询</title>
    <style>
        .box1 {
            height: 400px;
            background-color: aqua;
            flex: 1 1 auto;
            margin: 10px;
        }

        .box2 {
            height: 200px;
            background-color: red;
            flex: 1 1 auto;
            margin: 10px;


        }

        .container {
            display: flex;
            flex-direction: row;
            align-items: flex-start;
        }

        @media screen and (max-width: 750px) {
            .box1 {
                height: 400px;
                background-color: aqua;
                flex: 1 1 auto;
                /* min-width: 750px; */
                margin: 10px;

            }

            .box2 {
                height: 200px;
                background-color: red;
                flex: 1 1 auto;
                margin: 10px;


            }

            .container {

                display: flex;
                /* flex-direction: row; */
                flex-direction: column;
                /* flex-wrap: wrap; */
                align-items: stretch;
            }
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="box1"></div>
        <div class="box2"></div>
    </div>

</body>

</html>